I also shoot bows with shoot XB 30's.......
Like every other scope, Dial it in right on the money at 20 yards then replace the elevation adjustment cap and Leave It there. I would then adjust your speed ring somewhere between 350 and 360 fps. At this point you will no longer touch the elevation knob. Now set your target at exactly 40 yards. Use a bench and a good solid rest to assure your solid on target.
Shoot an arrow... if it hits low, turn your speed ring "Down'" to say 340 fps and shoot again... if hitting high. "Raise" the speed on the speed ring to 365-370 fps and shoot again... continue adjusting THE SPEED RING only, to adjust elevation.
If you have a very calm day with no wind and notice that at this longer range you perhaps hit left or right a bit,
Remove the side cap on your scope and make fine adjustments left or right until you hit your aiming point.
Since your point seems to move after sighting in, I would immediately after hitting the "Sweet Spot", wrap electricl black tape around the speed ring where it meets the tube. This should elliminate any shift due to the speed ring moving..
If after previously tightening all screws prior to attempting to sight your scope in and applying blue locktite and letting it set over night to cure. ...and assuring the tape is still in place on the speed ring and that it has not moved, you should now be "on" and adjusted for any range you would reasonably wish within the limits of your bow with that particular bow and the arrows you are shooting...
You can confirm your settings by shooting with the "Correct" crosshair , being the 2 one down, at 30 yards, and then the 4 th one down at 50 yards..... If it does not work out, or the point has shifted considerably,
I would suspect a faulty scope and return it for repair or replacement.
I hope this method helps you out.
Camo Micro 335 gen. ll " XB30 SR Pro, TT
Camo Matrix 350 SE Leupold Crossbones
Camo Matrix 380 & XB30 SR Pro, w/Boo Trigger
all w/Camo Munch mounts
Sweet 44 yr. old 73 Bronco